Title:	Firing-Triggered LID (FT-LID) of the Carrier Lifetime in Cz-Si
Author(s):	M. Winter, L. Helmich, D.C. Walter, J. Schmidt
Keywords:	Defects, Degradation, Lifetime, Silicon, LID
Topic:	Silicon Materials and Cells
Subtopic:	Feedstock, Crystallisation, Wafering, Defect Engineering
Event:	37th European Photovoltaic Solar Energy Conference and Exhibition
Session:	2DV.2.15
Pages:	462 - 467
ISBN:	3-936338-73-6
Paper DOI:	10.4229/EUPVSEC20202020-2DV.2.15
Price:	0,00 EUR
Document(s):	paper

Abstract/Summary:

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‘Light-Induced Degradation’ (LID) effects of the carrier lifetime are present in many different silicon materials used in the production of solar cells. In this contribution, we present an approach to separate the boron-oxygen (BO) LID effect observed in boron-doped Czochralski-grown silicon (Cz-Si) from an additional firing-triggered LID (FT-LID) effect. We perform BO degradation/deactivation cycles by alternating illumination and dark annealing (DA) steps at 200 °C, while recording the changes in the carrier lifetime. Our measurements show that – despite some similarities – the observed FT-LID effect in Cz-Si is different to the ‘Light and elevated Temperature Induced Degradation’ (LeTID) effect reported on multicrystalline silicon (mc-Si) materials. In particular, the time constants of the lifetime degradation differs by at least a factor of 10 under the same experimental conditions. In addition, experiments where multiple alternating light degradation, regeneration and DA steps were performed show a different behavior between FTLID in Cz-Si and LeTID in mc-Si. Although FT-LID as well as LeTID are both triggered by fast-firing, which makes it very likely that hydrogen participates in both defect reactions, the detailed defect physics seems to be different.